The present invention relates to applicator used to insert a tampon into vagina, thereby to absorb menstrual blood and to clog said vagina.
As the applicator for this purpose, there has already been used in practice the construction comprising a plastic outer sleeve adapted to accommodate therein a tampon and a plastic inner sleeve slidably telescoped into the outer sleeve so as to extrude the tampon through a front open end of the outer sleeve. However, such applicator of well known art tends to be bulky in its length and inconvenient for packaging as well as for being carried with user.
To overcome such inconvenience, the improved applicator has been proposed, as disclosed by Japanese Utility Model Publication No. 59-9621 and Japanese Patent Publication No. 60-27303, in which the inner sleeve comprises a first inner sleeve member and a second inner sleeve member slidably telescoped into the first inner sleeve member, and a rear end of the first inner sleeve member and a front end of the second inner sleeve member being provided with stoppers so that these rear and front ends are automatically interlocked by pulling the second inner sleeve member rearwards in use of a tampon.
The applicator disclosed by Utility Model Publication No. 59-9621 is shown by FIGS. 8 and 9. FIG. 8 is a fragmentary section illustrating the applicator of prior art as a first inner sleeve member and a second inner sleeve member constituting together the inner sleeve are not interlocked, and FIG. 9 is a view similar to FIG. 6 but illustrating the applicator as said sleeve members are interlocked. A plastic inner sleeve 2 slidably telescoped into a plastic outer sleeve 1 comprises a first inner sleeve member 3 and a second inner sleeve member 4 slidably inserted into the first inner sleeve member 3. The first inner sleeve member 3 is provided adjacent and at the rear end with projections 5 formed by partially cutting and bending inwards the material and the annular projection 6 directed radially inwards, respectively, while the second inner sleeve member 4 is provided at its front end with the annular projection 7 circumferentially extending around the outer periphery thereof so that the annular projection 7 may ride across said projection 5 against elasticity thereof and be interposed between the projections 5 and the annular projection 6 when the second inner sleeve member 4 has been completely pulled rearwards.
The variant of this well known construction is illustrated by FIGS. 10 and 11 corresponding to FIGS. 8 and 9, respectively. This variant is basically similar to the construction as illustrated by FIGS. 8 and 9 except that the first inner sleeve member 3 is gradually diameter-reduced rearwards and provided on the inner periphery at its rear end with the annular groove 8 while the second inner sleeve member is provided on the outer periphery at its front end with the annular projection 9 adapted to be engaged in said annular groove 8 when the second inner sleeve member 4 has been completely pulled rearwards.
The applicator disclosed by Patent Publication No. 60-27303 is shown in FIGS. 12 and 13 corresponding to FIGS. 8 and 9. The applicator is fundamentally similar to those as illustrated in FIGS. 8 through 11, as will be apparent from FIGS. 12 and 13, except that a second inner sleeve member 4 is provided on the outer periphery of its front end with projection 11 and, with a spacing axially behind the projection 11, non-annular projections 12 diametrically opposed to each other and directed towards the projection 11 while the first inner sleeve member 3 is provided on the inner periphery at its rear end with the projection 13 adapted to be interposed between the projection 11 and the non-annular projections 12 when the second inner sleeve member 4 has been pulled rearwards.
Referring to these figures, reference numeral 15 designates the conventional tampon including the pull-chord 16.
In such applicator, it has been general in practice that the outer sleeve 1 is formed as a cylindrical piece having a relatively small diameter, for example, of 10 to 13 mm so as to be inserted into vagina without any damage of vaginal membrane and the tampon 15 accommodated in this outer sleeve is formed as a round rod by compressing relatively bulky absorbent so that the outer periphery of the tampon may be in close contact with the inner periphery of the outer sleeve 1 when inserted thereinto in view of requirement that the tampon should absorb menstrual blood as plenty as possible and effectively clog vagina by swelling. Accordingly, the inner sleeve 2 is encountered by a certain degree of resistance when the tampon is extruded by the inner sleeve 2 through the front end of the outer sleeve 1. Such resistance is further enhanced by a pressure necessary to spread the petal-like segments normally closing the front end of the outer sleeve 1. It should be understood that these petal-like segments are measures to facilitate insertion of the outer sleeve 1 into the opening of vagina and employed by the previously mentioned applicators of the prior arts. Furthermore, depending upon the posture taken by user during inserting the tampon into vagina, the tampon may strike against vagina wall and cause a resistance. In any cases, the inner sleeve 2 is encountered by more or less resistance during a period from inserting the tampon through the opening of vagina to final positioning it into the desired location within vagina by extruding operation of said inner sleeve. It is important, therefore, that the interlocking effect to be established between the first inner sleeve member 3 and the second inner sleeve member 4 constituting together the inner sleeve 2 should be sufficiently stable to overcome said resistance.
The outer sleeve 1 of a relatively small diameter should be molded from material as soft as possible and correspondingly requiring adequate strength and thickness because the outer sleeve 1 is destined to be inserted into vagina. As it will be obvious, the first inner sleeve member 3 should be of a diameter sufficiently small to be inserted into the outer sleeve 1 and the second inner sleeve member 4 should be of a diameter sufficiently small to be inserted into the first inner sleeve member 3. The inner diameter of the second inner sleeve member 4 must be adequate to enable the pull-chord to pass therethrough. With a consequence, the first inner sleeve member 3, the second inner sleeve member 4, the projections 5, 12 and others should necessarily have relatively small thicknesses. It is practically difficult, for the reason of said requirements, to mold the first inner sleeve member 3 and the second inner sleeve member 4 of thicknesses larger than approximately 1 mm from synthetic resin. (1) With the applicator as illustrated by FIGS. 8 and 9, it is practically difficult to mold the interlocked portions of the first inner sleeve member 3 and the second inner sleeve member 4 which are subject to said resistance during insertion of the tampon, particularly the non-annular projections 5 destined to be directly subject to the pressure of the annular projection 6 with a thickness larger than approximately 1 mm, so the non-annular projections 5 may sometimes be bent or broken in the direction of said pressure, making operation of tampon extrusion impossible.
Also with the variant disclosed by FIGS. 10 and 11, the annular projection 9 is certainly engaged in the annular groove 8 against the elasticity of the first inner sleeve member 3, but this engagement is never stable and the annular projection 9 may be easily disengaged from the annular groove 8, making said operation of tampon extrusion impossible, because said engagement is easily established.
The applicator illustrated by FIGS. 12 and 13 is accompanied with, in addition to the above-mentioned problem, further problems as will be described below. In non-use, i.e., in the state that the second inner sleeve member 4 is still not pulled rearwards, the non-annular projections 12 remains yielding to a pressure exerted by the inner side of the first inner sleeve member 3 against the spring of the non-annular projections 12 themselves. Even when it is assumed that the second inner sleeve member 4 (inclusive of the non-annular projections 12) has been molded from synthetic resin of relatively high elasticity, said condition of yielding to the pressure lasting for a relatively long period may cause a fatigue in the non-annular projections 12 and, in consequence, said yielding may be fixed, so that the non-annular projections 12 may not restore their initial positions and, as a result, may not be engaged with the projection 13. There often elapse several months from the date of fabrication of the tampon to the actual use thereof by user, and this problem of fatigue is serious in view of this fact. Even if said engagement has been achieved, the pressure of the non-annular projections 12 exerted on the projection 13 may possibly lift the non-annular projections 12 in the direction opposed to the direction in which the pressure of the second inner sleeve member 4 is exerted, resulting in that the tips of the non-annular projections 12 protrude above the outer periphery of the first inner sleeve member 3 and the second inner sleeve member 4 can not be inserted into the outer sleeve 1.
In this manner, said applicators of the prior arts are far from the desired condition that the interlocking effect between the first inner sleeve member 3 and the second inner sleeve member 4 is reliable and stable sufficiently to overcome said resistance.
(2) Concerning the operation of tampon extrusion, the inner sleeve 2 is necessarily subject to more or less resistance as has been previously mentioned, this operation become difficult when the diameter of the inner sleeve 2 and particularly of its rear open end against which user's finger bears is small. Such inconvenience is further serious for the inner sleeve 2 consisting of the first inner sleeve member 3 and the second inner sleeve member 4 slidably telescoped into the first inner sleeve member 3 than for the inner sleeve 2 consisting of the single member, but none of the well known applicators has employed a measure to solve this problem. Certainly, the second inner sleeve member 4 is provided on the outer periphery of its rear end with the reinforcing annular rib, as seen from FIGS. 8 through 13, but the diameter of such annular rib can not solve said problem.
(3) With the above-mentioned applicators of the prior arts, as will be understood from FIGS. 8, 10 and 12, the second inner sleeve member 4 is not engaged with the first inner sleeve member 3 and the second inner sleeve member 4 easily displaces within the first inner sleeve member 3 in the axial direction even after assembly of the applicator and charging of the tampon into the outer sleeve 1 have been completed. Such displacement of the second inner sleeve member 4 disturbs operation of individually packaging the applicators.